The rapid development of computer image technology promotes the progress of a three-dimensional virtual reality technology. The construction basis of a three-dimensional scene in a three-dimensional virtual reality includes three aspects as follows. Firstly, a picture has a perspective effect which is the basis for viewing a three-dimensional world and is the basic requirement for generating a third dimension on the picture. Secondly, the picture has correct changes of brightness, darkness, virtuality and reality; in real world, an object may have corresponding bright part, dark part, projection, gloss and the like according to difference of the brightness, the colors, the positions and the quantities of light sources; further, the objects nearby are relatively high in aspects such as saturability, brightness and contrast of the color, and the objects far away are relatively low in these aspects. Thirdly, a space positioning effect on both eyes is achieved; when people views the object with eyes, the two eyes respectively observe the object from two angles, so that two observed pictures have tiny differences, and the brain mixes the two pictures into a complete picture and perceives a distance to the observed object according to a picture difference clue, and that is the space positioning of the two eyes.
So, the object in a three-dimensional virtual space is not defined through a plane, but is a three-dimensional object with a thickness and a subordination hierarchy relation, and the scene itself has relations such as the depth and the view angle. However, the equipment based on human-machine interaction still adopts a conventional two-dimensional screen, a conventional mouse and a conventional keyboard, and the cursor of the mouse also slides on a two-dimensional plane (in particular the screen).
FIG. 1 is a diagram showing the click and selection of an object in a three-dimensional scene implemented in the two-dimensional display. In the three-dimensional space, two-dimensional coordinates of the mouse in a three-dimensional scene window are acquired and transmitted to a virtual camera corresponding to the three-dimensional scene window, and a ray perpendicular to the three-dimensional scene window is generated in a direction of the position of the camera and extends in the three-dimensional scene, the first object intersected with the ray in the scene can be detected to indicate that the first object may be clicked.
As the ray and the object are intersected at a point, above method for clicking and selecting the object through the ray may not determine a scope for clicking and selecting the object; in the real world for example, a selection behavior and a semanteme for determining a selection scope may be defined, but the selection of the whole body of the object or a part of the object or the definition of the scope of the whole scene is difficult to be realized by clicking the object in the three-dimensional virtual reality scene; in addition, the object which is shaded, included or enclosed can not be mapped into the three-dimensional virtual scene window, so that the click and the selection of the included, the enclosed or the shaded object can be not realized.